Nozzles for abrasive-laden slurry



1968 R. J. GOODWIN ETAL 3,419,220

NOZZLES FOR ABRASIVE-LADEN SLURRY Filed Nov. 30, 1966 FIG.|

INVENTORS ROBERT J. GOODWIN JOSEPH L. PEKAREK PAUL W. SCHAUB UnitedStates Patent M 3,419,220 NOZZLES FOR ABRASIVE-LADEN SLURRY Robert J.Goodwin, Oakmont, and Joseph L. Pekarek and Paul W. Schauh, Penn HillsTownship, Allegheny County, Pa., assignors to Gulf Research &Development Company, Pittsburgh, Pa., a corporation of Delaware FiledNov. 30, 1966, Ser. No. 597,941 7 Claims. (Cl. 239-591) ABSTRACT OF THEDISCLOSURE The invention comprises a nozzle made of two or moredifferent materials, arranged in tandem, so that a section of the nozzlesubjected mostly to a particular type of wear can be made of aparticular material more highly resistant to that type of wear. Meansare disclosed to lock the nozzle in a drilling bit.

This invention pertains to nozzles, and particularly to a compositenozzle for use in hydraulic drilling of wells by means of high velocityjets of an abrasive-laden slurry, and to means for retaining such anozzle in a hydraulic drilling bit.

Nozzle war is a critical factor in the so-called jet drilling method, inwhich method the borehole is created substantially entirely by the highvelocity jets of abrasiveladen slurry, Hydraulic jet drilling allowssubstantially higher penetration rates than are obtainable withconventional rotary bits. Rotary bits create the borehole by mechanicalaction between cutting elements of the bit and the formation.

However, in the jet drilling method the highly erosive nature of theslurry passing through the nozzle tends to erode the nozzle rapidly.Drilling must stop when the nozzles become so eroded and enlarged thatthe pumping equipment is no longer able to develop the required cuttingjet velocity through the nozzle exits because of the pressure lossesassociated with the higher flow rates through the pipe required by theenlarged nozzles. When this occurs, it is necessary to pull the drillstring and bit out of the hole, replace the bit with a new bit, orreplace the nozzles, and then reinsert the drill string. This is a timeconsuming operation, and a very expensive one considering the high costof maintaining a drilling rig and its crew in the field. Hence, it is aprimary object of the present invention to provide an improved nozzlesuitable for use in jet drilling which will have a relatively longuseful life.

The invention comprises a nozzle composed of a plurality of sectionsarranged in tandem. Each section is fabricated from a different grade ofmaterial, each having a particularly physical characteristicadvantageous at the location in the nozzle in which that section islocated. Many different materials and combinations of materials could beused. Some examples are diamond, ceramic materials, boron carbide, andtungsten carbide.

Tungsten carbide has been found to be a particularly suitable materialfor fabricating nozzles used in jet drilling. However, there are variousdifferent grades of tungsten carbide and each of these grades has adifferent set of physical characteristics. The particularcharacteristics with which the invention is concerned are abrasionresistance and impact resistance. That is, resistance to wear fromabrasion or from impact between the nozzle material and the particles ofabrasive in the slurry. -It has been found that certain sections of thenozzle are subject more to wear from impact and certain other sectionsare subject more to wear from abrasion, than other sections. Theentrance end of the nozzle reduces the cross-sectional area of the flowstream to increase its 3,419,220 Patented Dec. 31, 1968 velocity, and issubjected to impact from the abrasive particles in the slurry. The exitend of the nozzle, which is formed into a cylindrical throat portion, issubjected more to abrasion wear because of the laminar like flow of theslurry therethrough. The central portion of the nozzle, wherein the flowstream is narrowed down in preparation for its passage through thethroat, is subject to both impact and abrasion wear, but to degrees lessthan the entrance section and the exit throat section, respectively.

The invention also comprises a method and apparatus for mounting thenozzle in a jet drilling bit, which comprises means to hold the nozzlesections locked into a suitable opening in said bit.

In the accompanying drawing forming a part of this disclosure: FIG. 1 isa front elevational view of a nozzle embodying the invention; FIG. 2 isa longitudinal crosssectional view taken on line 22 of FIG. 1; and FIG.3 is a partial, vertical, cross-sectional view through a bit showing thenozzle mounted therein.

Referring now in detail to the drawing, 10 designates a nozzle embodyingthe invention. Nozzle 10 is formed with a longitudinal through opening12. Opening 12 defines the operating characteristics of the nozzle, isshown diagrammatically only, and is not intended to representa preferredinternal cross-sectional shape. As will be obvious, the invention isapplicable to an elongated nozzle having an internal cross-sectionalshape.

Nozzle 10 comprises an exit section 14, a central section 16, and anentrance section 18. The direction of flow through the nozzle isindicated by the arrows marked Q, representing the flow direction of theabrasive-laden slurry.

Each of the sections 14, 16, and 18 is hollow, and the three sectionsare arranged in tandem to form through opening 12. The sections may bejoined together by any suitable means such as silver solder, brazing orthe like when it is desired to fabricate the nozzle alone, or they maybe held together in a bit by suitable locking means, as described below.Exit section 14 is is fabricated of a grade of tungsten carbide having ahigh resistance to wear from abrasion. Entrance section 18, which is thesection of the nozzle first subjected to the impact force of theabrasive particles in the slurry as the flow stream is reduced incross-sectional area, is fabricated of a different grade of tungstencarbide characterized by a high resistance to wear from impact. Thecentral section 16 is fabricated from a third grade of tungsten carbidehaving its abrasion resistance and impact resistance wearcharacteristics balanced, with the impact wear resistance characteristicbeing less than that of the material forming entrance section 18, andwith the abrasion resistance wear characteristic being less than that ofexit section 14. At present, a material high in both abrasion and impactresistance is not available.

Nozzle 10 is shown comprised of three sections, but it is to beunderstood that this is by way of example only, and a nozzle comprisingtwo sections would be used in a shorter nozzle where the over-all lengthis such that there is in effect no central section, and the flow stream,as far as the wear characteristics with which the invention is concernd,goes directly from the entrance section to the exit section.

Suitable grades of tungsten carbide are manufactured by KennametalCompany of Latrobe, Pa. These various grades are described in theircatalogue entitled, Properties of Kenn-ametal Hard Carbide Alloys.Copyright 1964, wherein there can he found tables listing numericalvalues for physical characteristics of the materials manufactured bysaid company including abrasion resistance and impact resistance. Thecited catalogue also sets forth the test conditions by which thesevalues were obtained. Referring to said catalogue at page 10, a suitablegrade fo tungsten carbide for use in section 14 is designated gradeK701; for section 16, grade K8; and for section 18, grade K68.

Boron carbide and diamond are also suitable materials for use in exitsection 14, because both of these materials are very resistive to Wearfrom abrasion, and the fact that they are both brittle and hence notresistive to wear from impact, does not detract from their usefulness inthe exit section.

Referring to FIG. 3, there is shown a diagrammatic cross-sectional viewthrough a corner of a jet drilling bit showing the invention in use. Itwill be understood that the showing of FIG. 3 is intended to beillustrative only of the method and means of mounting the nozzle of theinvention in a jet drilling bit, and is not to be limited to vertical asshown, since nozzles are mounted at various angles in practice. Jetdrilling bit 20 comprises a bottom Wall 22 and a side wall 24, whichtogether form a hollow slurry receiving chamber 26 within the bit. Bit20 also comprises a bottom plate 28 formed of hard, abrasion resistantmaterial, to protect the bit from excessive wear by backsplash ofabrasive particles from the bottom and side walls of the borehole.

Mounted in bottom wall 22 and bottom plate 28 is a nozzle 10a, similarto the nozzle 10 of FIGS. 1 and 2', except that exit section 14a ofnozzle 10a is formed with an external taper 30 which cooperates with amating female taper formed in bottom plate 28 to limit movement of thenozzle 10a downwardly and outwardly of the bit, to hold the nozzle inplace. Nozzle 10a also comprises a center section 16a and an entrancesection 18a similar to those respective parts of nozzle 10. Abovetapered portion 30, bottom plate 28 and bottom wall 22 are formed with acylindrical opening 32 of a suitable diameter to snugly fit the externaldiameter of nozzle 10a. Means are provided to hold nozzle 10a firmly inplace in composite opening 30 and 32, and yet to selectively permitremoval of the nozzle if it should become worn. To this end a nozzlelocking sleeve 34 is provided. Sleeve 34 comprises an internal diameter36, substantially equal to the external diameter of nozzle 10a,extending through substantially its entire length. At its upper end,sleeve 34 is provided with an overhanging lip or flange 38 having aninternal diameter smaller than the external diameter of nozzle 10a, butlarger than the largest diameter of the internal longitudinal opening ofthe nozzle. Thus, flange 38 overlies the upper end of the nozzle to holdthe nozzle firmly in place against taper 30, and yet does not interferewith the flow stream of the abrasive-laden slurry through the nozzle.The lower end of sleeve 34 is formed with screw threaded 40 whichcooperate with mating threads formed in an opening formed in bottomplate 22 above opening 32. The upper external portion 42 of sleeve 34above threads 40 may be formed into a hex nut, or with holes for aspanner wrench, or with any other suitable means, for tightening thesleeve by means of threads 40 to lock the nozzle in place.

The sections 14a, 16a and 18a of nozzle 10a may be held in place solelyby tension applied by locking sleeve 34. In applications wherein higherpressures and/or severely adverse conditions are encountered, brazing orother joining means between the sections may be employed.

The invention has advantages over prior nozzles fabricated all in onepiece. It is simpler and less expensive to fabricate a nozzle insections rather than in one piece, and easier to control theconfiguration of the internal profile. Also, it is possible todisassemble a composite nozzle and replace only the section that isworn, which is impossible in a one piece nozzle. This advantage isenhanced in those applications where the sections of the nozzle are heldtogether solely by the force of the locking means, since the step oftaking apart the solder or brazed joints is avoided. Thus, in effect, areusable nozzle is provided, at a saving of approximately one-third thecost of a new nozzle.

While the invention has been described in some detail above, it is to beunderstood that this detailed description is by way of example only, andthe protection granted is to be limited only within the spirit of theinvention and the scope of the following claims.

We claim:

1. A bit for drilling earth boreholes by means of high velocity jets ofan abrasive-laden slurry having an internal slurry receiving chamber,comprising an elongated nozzle consisting of a plurality of nozzlesections arranged in tandem, said nozzle sections being formed withaligned openings to form a longitudinal through opening through saidnozzle, said plurality of sections including an entrance nozzle sectionand an exit nozzle sections, said exit nozzle section consisting of afirst material having a high resistance to wear by abrasion, saidentrance nozzle section consisting of a second material having a highresistance to wear by impact, said nozzle including a central nozzlesection disposed between said exit and entrance nozzle sections, saidcentral nozzle section consisting of a third material having aresistance to wear by impact less than that of the material constitutingsaid entrance section and a resistance to wear by abrasion less thanthat of the material constituting said exit section, and locking meansto lock said nozzle in said bit with the entrance end of said entrancesection Within said chamber and with the exit end of said exit sectionoutside of said chamber.

2. The combination of claim 1, said locking means comprising a lockingsleeve formed with radially inwardly ext-ending flange means cooperablewith the entrance end of said entrance section, said flange means beingpositioned outwardly of the entrance opening of said entrance section,whereby said flange means are positioned out of the flow stream of theslurry entering said nozzle, and said locking sleeve being formed with ascrew thread cooperable with a mating thread in said bit to lock saidnozzle in said bit.

3. The combination of claim 1, means on said bit cooperable With meanson said exit section to limit movement of said nozzle with respect tosaid bit in one direction, said movement limiting means comprisingmating tapers formed on the outside of said exit section and in asuitable opening formed in a wall of said bit defining said chamber.

4. The combination of claim 1, means to join the exit end of saidentrance section to the entrance end of said central section, and meansto join the exit end of said central section to the entrance end of saidexit section.

5. The combination of claim 4, said joining means comprising silversolder.

6. A bit for drilling earth boreholes by means of high velocity jets ofan abrasive-laden slurry having an internal slurry receiving chamber,comprising an elongated nozzle consisting of a plurality of nozzlesections arranged in tandem, said nozzle sections being formed withaligned openings to form a longitudinal through opening through saidnozzle, said plurality of sections including an entrance nozzle sectionand an exit nozzle section, said exit nozzle section consisting of afirst material having a high resistance to wear by abrasion, saidentrance nozzle section consisting of a second material having a highresistance to wear by impact, and locking means to lock said nozzle insaid bit with the entrance end of said entrance section within saidchamber and with the exit end of said exit section outside of saidchamber, said locking means comprising a locking sleeve formed withradially inwardly extending flange means cooperable with the entranceend of said entrance section, said flange means being positionedoutwardly of the entrance opening of said entrance section, whereby saidflange means are positioned out of the flow stream of the slurryentering said nozzle, and said locking sleeve being formed with a screwthread cooperable with a mating thread in said bit to lock said nozzlein said bit.

7. A bit for drilling earth boreholes by means of high velocity jets ofan abrasive-laden slurry having an internal slurry receiving chamber,comprising an elongated nozzle consisting of a plurality of nozzlesections arranged in tandem, said nozzle sections being formed withaligned openings to form a longitudinal through opening through saidnozzle, said plurality of sections including an entrance nozzle sectionand an exit nozzle section, said exit nozzle section consisting of afirst material having a high resistance to wear by abrasion, saidentrance nozzle section consisting of a second material having a highresistance to wear by impact, locking means to lock said nozzle in saidbit with the entrance end of said entrance section within said chamberand with the exit end of said exit section outside of said chamber, andmeans on said bit cooperable with means on said exit section to limitmovement of said nozzle with respect to said bit in one direction, saidmovement limiting means comprising mating tapers formed on the outsideof said exit section and in a suitable opening formed in a wall of saidbit defining said chamber.

References Cited M. HENSON WOOD, JR., Primary Examiner.

M. Y. MAR, Assistant Examiner.

US. Cl. X.R.

